Having done e-bike mods in the past, rear-dropouts tend to be stronger than front-dropouts, and on any steel bike you can put a lot of torque on the front dropouts.
Only problem with rear-dropouts is accommodating the gearset, which they cleverly handled by eliminating the gearset; that will suck if you run out of power downhill from your destination, but will otherwise work fine.
That would indeed suck! I can see why they didn't incorporate a cassette body (and the chain clearance issues that would entail: basically everything they have on the right side now would have to be moved to the left side) but it does make the final product seem less like a bicycle. (I know, this is sacrilege to the fixie folks. Meh.)
I had another thought: maybe through judicious sizing of (front) chainrings and the freewheeling cog one could get something that could climb a hill? Will widespread adoption of this device encourage development of a front derailleur that can handle more than three rings?
Only problem with rear-dropouts is accommodating the gearset, which they cleverly handled by eliminating the gearset; that will suck if you run out of power downhill from your destination, but will otherwise work fine.